In its simplest form the waveform generated by a vertical timebase circuit comprises a linear sawtooth waveform. This waveform is typically generated by charging and periodically discharging a ramp capacitor.
In practice problems arise in utilising a linear ramp current. The external driver circuit which applies the generated ramp current to the vertical deflection coils is non-linear. Secondly the picture tube may not have a linear deflection versus current characteristic.
This invention seeks to provide a timebase circuit in which the above mentioned problems are mitigated.